Athletic playing fields such as football and soccer fields or running tracks are typically provided with a drainage channel system formed alongside the playing surface for receiving and collecting liquid runoff. In particular, running track surfaces may include a polymeric surface which is substantially impervious, making adequate drainage very important. Artificial and natural turf playing surfaces are generally more porous than a running track and may include other drainage systems thereunder, but a drainage channel along the edge of the playing surface may nevertheless be important for draining excess runoff.
For outdoor athletic facilities, a drainage channel system is mainly used for draining rainwater. However, a drainage channel system may also be important in indoor or covered athletic facilities for draining other liquids such as water or solvents used to clean the athletic surface. In either instance, the particular athletic surface may be slightly crowned or sloped from the center to the edges to facilitate drainage therefrom.
A drainage channel system typically includes an elongate and substantially continuous drainage channel extending around the periphery of the athletic surface. The drainage channel may be positioned along the border between athletic surfaces of different types. For example, the drainage channel may be located between a polymeric running track and an artificial turf or natural grass playing field.
An elongate grate is typically provided over the drainage channel so as to cover the open top of the channel in order to prevent people from unwittingly stepping into the open channel and/or to prevent relatively large objects from entering the channel and partially blocking the flow of liquid therethrough. While the grate effectively covers the open top of the drainage channel, the drainage system and, in particular, the portion of the grate which is exposed to the surface can decrease the aesthetic appeal of the athletic playing fields. The drainage channel can also be slightly sloped to enhance flow within the channel. Further, the drainage system can include one or more catch basins along the channel to collect solid debris and pass the liquid to effluent pipes for removal from the playing field.
As will be apparent to those skilled in the art, the edges of an artificial turf surface must generally be anchored or secured in a fixed position to prevent unwanted movement of the artificial turf surface. Thus, several drainage systems have been developed which not only receive runoff from the artificial turf surface, but also anchor an edge of the artificial turf surface.
For example, a drainage system is commercially available under the trademark ACO SPORT.RTM. from Aco Polymer Products, Inc. which also serves to anchor the edge of an artificial turf surface. The ACO SPORT.RTM. drainage system includes a number of drainage channel configurations which, in some embodiments, are covered by a variety of grates and/or a polymer concrete hard cover. More specifically, Model Nos. AS-130 and AS-145 of the ACO SPORT.RTM. drainage system not only provide drainage for the adjacent playing surfaces, but also anchor an edge of the artificial turf surface.
In particular, ACO SPORT.RTM. drainage system Model No. AS-130 includes a grate which extends across the open top of a drainage channel. The opposed edges of the grate include a vertically extending downturned portion which cooperates with an upper portion of a sidewall of the drainage channel to clamp the edge of the artificial turf surface therebetween. However, the artificial turf surface which is clamped between the grate and the sidewall of the drainage channel has a finite thickness. Thus, in embodiments in which the AS-130 drainage channel extends between an artificial turf surface and a polymer running track, the grate may be slightly unlevel since the artificial turf surface is clamped between the edge of the grate and the sidewall of the drainage channel which is adjacent to the artificial turf surface.
Regardless of the manner in which an artificial turf surface is anchored, it is desirable to maintain the artificial turf surface in a taut condition to prevent looseness between the artificial turf surface and the subsurface layers. Thus, the artificial turf surface is preferably stretched taut during the installation and anchoring process to minimize, if not eliminate, undesirable looseness as the artificial turf surface expands and contracts as the temperature increases and decreases, respectively. Since the grate of the ACO SPORT.RTM. Model No. AS-130 drainage system secures the edge of the artificial turf surface in the same position to which the artificial turf surface was previously stretched, however, the artificial turf surface must be fully stretched to the desired tension prior to installing the grate over the open top of the drainage channel.
In addition, ACO SPORT.RTM. drainage system Model No. AS-145 does not include a grate, but, instead, includes a polymer concrete hard cover which extends over at least a portion of the open top of the drainage channel. The polymer concrete hard cover includes a clamping jaw which receives and secures an edge of the artificial turf surface. The ACO SPORT.RTM. Model No. AS-145 drainage system also includes a border or curb formed of ethylene-propylene diene monomer ("EPDM") which delineates the boundary between an artificial turf infield and a surrounding running track. The artificial turf infield and the surrounding running track are at different levels, however, such that athletes or others must step over the EPDM border to pass between the artificial turf infield and the surrounding running track.
In addition to securing an edge of the artificial turf surface, the ACO SPORT.RTM. Model No. AS-145 drainage system also receives runoff from the adjacent playing surfaces. Since the polymer concrete hard cover covers at least a portion of the open top of the drainage channel, runoff is received from the adjacent playing surfaces through a number of openings defined within an edge portion of the polymer concrete hard cover under the EPDM border which borders the running track. Thus, runoff from the artificial turf surface must initially drain onto the surrounding track prior to passing through the openings and into the drainage channel.
The U.S. Pat. No. 4,312,504 to L. Rutledge, et al. also describes a system for anchoring artificial turf surfaces. In particular, the Rutledge '504 patent describes a system for converting from an artificial turf surface, such as a football field, to a natural grass or dirt surface, such as the infield area of a baseball diamond. As illustrated in FIG. 1 of the Rutledge '504 patent, the edges of a pair of adjacent artificial turf surfaces can be wedged into a slot defined in a concrete foundation. A rope-like retainer strip can then be forced down into and along the length of the slot to further secure the respective edges of the artificial turf surfaces. In order to remove one of the artificial turf surfaces to expose the underlying dirt surface, the retainer strip and the edges of the artificial turf can be removed from the slot defined by the concrete foundation. The edge of the remaining artificial turf surface can then be stretched over the concrete foundation, including over the slot, so as to be anchored to a wooden nailer.
As shown in FIG. 1 of the Rutledge '504 patent, an upper end of the slot is open to the ground and a lower end is in fluid communication with a sloped drain conduit to convey runoff from the artificial turf surfaces which enters the slot to a central collection area. However, runoff from the artificial turf surfaces must enter the drain conduit via the slot which is at least partially filled by the edges of the artificial turf surfaces and, in some instances, by a retainer strip. Thus, the capacity of runoff which the drainage system of the Rutledge '504 patent is able to receive may be undesirably limited in some instances.
European Patent Application No. EP 109,065A to K. Broermann which was published May 23, 1984 also describes a drainage system which can clamp the edge of an artificial turf surface. The drainage system of the Broermann application includes a number of stone blocks which define longitudinal slots into which an edge of the adjacent artificial turf surface can be pressed. As illustrated in the Broermann application, the slots include an undercut portion defined in one wall thereof. In order to secure the edge of the artificial turf surface within the slot, a number of wedges having a serrated surface can be inserted into the slots to press the edge of the artificial turf surface into the undercut portion of the slot.
In addition to securing the edge of an artificial turf surface, the slots defined by the stone blocks of the drainage system of the Broermann application are connected to drainage pipes to provide drainage of the artificial turf surface. However, runoff from the artificial turf must enter the drainage pipes via the slots defined by the stone blocks which are at least partially filled by the wedges and the artificial turf surface. Thus, the capacity of runoff which the drainage system of the Broermann application is able to receive may also be undesirably limited in some instances. In addition, the slots defined by the stone blocks are not covered by a grate, but are, instead, at least partially filled by the wedges. Therefore, the resulting upper surface defined by the artificial turf surface, the stone blocks and upper portions of the wedges may be somewhat unlevel and at least some portions of the slot may be fully exposed to the surface.
As described above, several drainage systems have been developed which not only receive runoff from an artificial turf surface, but also anchor an edge of the artificial turf surface. However, these drainage systems still do not fully address the needs of modern athletic playing surfaces. For example, the prior drainage systems do not further tension the artificial turf surface during the anchoring process so as to insure that the artificial turf surface will remain taut as the temperature fluctuates. In addition, the drainage capacity of some of these prior drainage systems is to be at least somewhat limited. Further, at least some of these prior drainage systems do not maintain the athletic playing surfaces which are adjacent to the opposed sides of the drainage channel in a level orientation in order permit athletes and others to more readily pass thereover.